On her grandmother's West Clare farm in 1980, twelve-year-old Hanna Madigan is holding the torso of a chicken her father has just decapitated, its headless body still "shitting out from under the black tail feathers, in squirts that mimicked the squirting blood".

Twenty-five years later, Hanna is now a drunken 37-year-old, and from the floor of her suburban Dublin kitchen she watches as "the blood oozed away from her, across the white floor tiles... so much fucking blood".

Meanwhile, in the New York of 1992, there are recollections of "blood everywhere" as the friends and lovers of Hanna's gay brother, Dan, succumb to Aids; and in the Mali of 2002, where Hanna's other brother, Emmet, works for a care agency, there is blood and then "more blood" leaking from a stray dog that he and his girlfriend have tried to mind but that has been poisoned by locals.

Welcome yet again to the fictional world of Anne Enright and to her fascination with bodily excrescences, affronts and indignities, whether they be animal or human. In the case of Constance, Hanna's older sister, they're human as "buttons gaped over breasts that had done their time", though in Dan's New York they mainly concern penises, with Billy "on a mission to eat risotto and much cock" and with everyone in a lustful tizzy about Dan's "uncut Irish cock".

Those who are familiar with Enright's Man Booker-winning The Gathering (2007) will be acquainted with her relish for such physical details, and at the outset of The Green Road they may also think the storyline familiar - after all, here is the promise of another gathering, even if the journey home here has more to do with guilt about absence than about any extreme feelings of acrimony.

In fact, the book is quite different from The Gathering and more life-affirming, too, as our fiction laureate conjures up the separate lives these grown-up children have been leading and gives them all their due as individuals who've either had to flee from or daily cope with their demanding widowed mother Rosaleen, "a woman who did nothing and expected everything".

That's a good line and Enright has many others, as in the dry aside that Emmet had spent "twenty years saving a world that remained unsaved", though it's Emmet who is perhaps the most congenial of the siblings - the thirty-six pages about his time in a Mali village with his frail but fiercely determined girlfriend and co-worker Alice are so evocative and so true to transient experiences that the reader may wish the author had written a whole novel about these lives.

Indeed, just like Rosaleen, who has always doted on Dan, readers will have their own favourite offspring here, with put-upon eldest sibling Constance, who stayed in West Clare and married a decent and dutiful man, gradually emerging as a person of real substance and complexity - even if, in the dying days of Celtic Tiger Ireland, "she got her hair done in a place so posh it didn't look done at all".

The drink-addicted Hanna, whose acting career is in tatters and who's living with a man "who hated her and slept with her anyway", cuts a poignant figure, though the author seems less interested in her than in the others, and you end up wanting to know more about her and what makes her tick.

You may wish, though, that you knew less about Dan and his New York lifestyle, because it's in this chapter that the book's tone falters somewhat. We're all aware that the sexual lives of gay men can be more promiscuous than those of heterosexual men, whose negotiations with women usually involve a degree of circumspection and an observance of defined rules, but if you're to accept this account gays think of little or nothing other than sex.

Greg is "so desperate for a blow job he thought if he didn't get one he would lie down like an old dog and whine", and as for Billy and Dan: "They had bitterness and blame and pointless sex. They had sudden sex. They had sex-while-weeping, and tender sex, and rough sex, and leave-taking sex". And on the plane trip home, Dan "carried a boner with him all the way back to Dublin". That must have been uncomfortable.

The green road of the title, a road across the Burren that has carried a special meaning for Rosaleen since her courting days, is where she flees to on Christmas night, much to the consternation of her children, though the book itself closes in the house Emmet has rented on a nondescript estate outside Dublin, with Rosaleen, having sold the family home, arriving at his doorstep.

It's either an enigmatic ending or an unresolved one - Constance has been diagnosed with breast cancer, Hanna is drunkenly trying to bring up a baby, Dan is about to marry Ludo in New York, and Emmet's career seems in abeyance. Indeed, the author has made you feel so complicit in these people's lives that you may end up wishing for a sequel about their lives to come.

Full list of 2015 winners

The full list of winners in the Bord Gáis Energy Irish Book Awards 2015 is: